Leaders Exeter Chiefs suffered a third Premiership defeat of the season at Gloucester, while Wasps moved into the top four.
Callum Braley won successive World Rugby Under-20 Championships with England but has been named in the latest Italy training squad.
Saracens and Racing 92 secured home quarter-finals in the Champions Cup but the hopes of Exeter Chiefs are over after defeat at Munster.
Joey Carbery, Rory Scannell, Keith Earls and Andrew Conway were among the tries as Munster overpowered Gloucester.
After four weeks out, England fly-half Danny Cipriani is back for Gloucester as they take on Munster on Friday.
Bath finished the game with 11 men as they suffered defeat to lowly Worcester Warriors in the 98th minute.
Calum Clark and David Strettle scored second-half tries as Saracens rallied to beat Worcester Warriors, while Harlequins held off Wasps.
Bath are into the Premiership's top six after beating Wasps, while Gloucester won at Newcastle Falcons.
Danny Cipriani's hopes of catching Eddie Jones' eye again before the Six Nations appear to be slim after he suffered an injury blow.
Ulster and Exeter Chiefs enhanced their chances of qualifying for quarter-finals of tEurope's premier club rugby competition on Friday.
Eddie Jones has not been convinced by the in-form Danny Cipriani this season, but there are no hard feelings from the England fly-half.
There were wins for Gloucester, Toulon and Leinster in the European Champions Cup on Saturday.
Alex Allan's dismissal did not prove costly as Glasgow Warriors beat the Scarlets, while Leinster scored 59 in a victory over the Dragons.
Defending champions Saracens have won each of their opening nine Premiership fixtures as they stayed perfect by beating Wasps 29-6.
There were wins in the Premiership on Saturday for Exeter, Sale and Wasps, the latter triumphing despite a stunning Bristol fightback.
Gloucester had Danny Cipriani back from a ban and the fly-half was instrumental in their bonus-point 36-13 win over Leicester Tigers.